Base plates are used in ostomy appliances to attach ostomy bags to the skin of a user having a stoma, the user also being referred to as an ostomist.
A base plate is typically formed by a backing layer or top film on which a skin friendly adhesive is disposed. A through-going hole is arranged in the base plate to receive a stoma so that the base plate may be adhered to the skin surrounding the stoma.
In order to collect output from the stoma, the opening of an ostomy bag is arranged around the through-going hole. The ostomy bag may, for example, be arranged by welding the bag to the backing layer of the base plate. In the art, this is referred to as a one-piece ostomy appliance. Alternatively, a coupling arrangement, typically either adhesive or mechanical, may be arranged so that ostomy bags can be detachably mounted on the base plate. This allows the bag to be changed when full without detaching the base plate from the skin. In the art, this is referred to as a two-piece ostomy appliance.
A number of ostomists develop so-called sunken/retracted stomas. Due to inevitable post-surgical and ongoing physiological changes of the ostomist's body, the stoma may from the outset or over time sink or retract into the abdomen creating a recess in the body surface where the stoma is placed. Applying a standard planar base plate around a retracted stoma would, for one thing, leave the area around the stoma uncovered (gap between the peristomal skin surface and adhesive surface of base plate) and thereby exposed to the output from the stoma. Moreover, in some cases the stoma may be retracted to such a degree that it cannot extend through the through-going hole in the base plate thus resulting in frequent leakage problems. In order to address the issue of retracted stomas, and the encountered frequent leakages, convex base plates have been developed.
Traditionally, such convex base plates are made by providing a relatively stiff pre-cast or moulded unit of convex shape and attaching it to one side of an adhesive wafer whereby the base plate obtains its convexity. Such products have been available on the markets for many years.
The primary purposes and effects of these convex base plates are that they are able to withhold the peristomal skin of the ostomist's body from collapsing (e.g. due to excess skin folds) and to increase the ability of the stoma to protrude adequately past the interface between the base plate and the body surface due to the reactive force provided by them and thus deposit the stomal output directly into a collecting bag for human body wastes. Thereby the risk of leakages is reduced since stomal output is less prone to end up underneath the adhesive surface of the base plate where it may attack and eventually disintegrate the adhesive seal.
Generally, however, since these products are relatively stiff and inflexible, they will not follow the movements of the user's body caused by physical activity very well. More severely, experience has shown that the use of these products may in some cases result in peristomal skin damage such as pressure wound ulceration, bruises and/or general skin irritation.
Moreover, the pre-cast or moulded unit of these convex base plates cannot be fitted to abutment with the stoma or even provided close to the stoma. Instead, they require some radial clearance between the innermost edge of the convex pre-cast or moulded unit and the stoma's surface.
This is due to a number of reasons: first of all, experience has shown that if a stiff unit is in direct contact with the mucus membrane of a stoma's surface, it tends to cut and irritate it, which may eventually cause the stoma to bleed and incur serious complications. Also, the pre-cast or moulded unit may prevent the stoma from expanding freely, the expansion(s) caused by the peristaltic movements of the intestine.
In addition thereto, the presence of such a radial clearance between the innermost edge of the pre-cast or moulded unit and the stoma-receiving through-going hole means that there will be a lack of adequate constant pressure against the skin surface, particularly in the immediate peristomal skin area. This lack of adequate pressure often means that the immediate peristomal skin of the user, between the innermost edge of the convex unit and the stoma's surface, is distanced axially in relation to the skin otherwise forced in position by the convex unit. This phenomenon increases the risk of leakages.
Moreover, almost all users need to perform some sort of customizing action to make a fresh appliance fit as precisely as possible to the shape of their stoma's surface (contour(s)) to provide the best possible security against leakages. To that end, almost every ostomy appliance, including those having a pre-cast or moulded convex unit, has a possibility to cut (e.g. with scissors) in the surface of the base plate to make it fit as good as possible. This is often facilitated by means of a small hole, referred to as a pre-cut hole, starter-hole or simply “pre-cut” provided in the center of the base plate by the manufacturer.
With regard to the traditional convex base plates, the presence of the pre-cast or moulded stiff convex unit sets a limit to the level of customization possible, in terms of the hole size and shape in such products, as it is not possible to cut the pre-cast convex unit.
One example of such a traditional and relatively stiff convex base plate is disclosed in EP748195.
In more recent years an increased variety of convex base plate products have been made available to ostomists. As every user has individual needs due to his or her unique body and stoma shape, experience has shown that the known stiff convex products fail to overcome each and every kind of those needs.
Particularly, if the recess in the body is relatively shallow, i.e. when the stoma is only retracted to a relatively small degree, a less bulky and stiff convex base plate may be appropriate. Furthermore, there has been a desire to alleviate at least some of the user-experienced discomfort caused by the stiffness and inflexibility of the known stiff convex base plates.
To overcome these and other needs, what is commonly accepted as “soft convex” base plates, have been developed. These have a much higher degree of flexibility than the stiff convex base plates and thus improve user comfort.
An example of a construction of such a soft convex base plate product available today comprises at least a layered structure where one layer is a skin friendly adhesive for attachment to an user's body, the adhesive layer being backed by a thermoplastic backing material that is provided at least partly with a convex shape by thermoforming the backing material either before or after application of the adhesive layer. Thus, the product's convexity in this case is achieved by thermoforming the backing into the desired convex shape.
Such soft convex products only provide low pressure to the peristomal skin as their convexity may be considered “reinforced” only by the thermoforming of the backing material. Therefore, they typically cannot increase the ability of the stoma to protrude adequately past the interface between the base plate and the body surface due to the lack of reactive force provided by them.
These soft convex products typically do not have any radial clearance between an innermost part of the thermoformed backing and the through-going hole, as the backing supports the adhesive over the whole surface thereof (in other words, the backing is the convexity providing element). Having to cut directly in the convex thermoformed backing material for customization to the stoma's surface, increases the risk of the resulting (cut) edge of the backing material harming and/or irritating the stoma's surface.
An example of a type of soft convex base plate is disclosed in EP1178766.
In view of the above described available solutions of today, there is a clear need to improve these so as to provide an ostomy appliance that can maintain a relatively constant pressure against the peristomal skin all the way to abutment with the stoma or in very close vicinity thereof while simultaneously provide the user with the possibility of customizing such a product to a very close fit with the shape of the stoma with a minimal risk of cutting and/or irritating the stoma. Particularly, in the case of convex products, the solution according to the present invention provides these advantages while also providing at least some of the flexibility known from soft convex base plates.